As generally known in the art, a paper shredder is an office appliance which rapidly and safely shreds secret paper sheets so as to dispose of it. A paper shredder has recently had a structure having an automatic paper supply function as well as a manual paper supply function as a basic function.
An automatic paper supply function refers to automatically supply a proper quantity of paper sheets. Although a large number of paper sheets is put at once on a paper supply part of an automatic paper supply apparatus, the paper sheets are divided into the proper number of sheets of paper as many as the paper shredder can shred at one time, and then are automatically input into the interior of the automatic paper supply apparatus several times.
Such an automatic paper supply function makes it possible to successively shred a large number of paper sheets by loading of paper sheets with no need to the user to input a sheaf of paper to be shredded into the paper supply part in each time, thereby increasing efficiency in work and convenience in use.
However, in a case of stapled paper sheets, the conventional paper shredder having an automatic paper supply function has to shred paper sheets only when its staple is removed. If the stapled paper sheets are shredded in a stapled state, particularly if the thickness of the stapled paper sheets exceeds the thickness of the number of paper sheets which the paper shredder can shred at one time, the shredding working through the paper shredder can not be progressed any more.
Furthermore, in the conventional paper shredder having an automatic paper supply function, a metallic pin or a sharped protuberance for controlling the quantity of paper automatically supplied is added to a feed roller thereof so as to allow several pieces of paper to be simultaneously supplied, thereby increasing performance in supplying paper. However, in this case, if the user's hand is scratched by the metallic pin or the sharped protuberance, a serious accident can be easily caused.